1. Field of the Invention
The mixing apparatus of the present invention is especially adapted for use in a program controlled automatic mold making system such as that disclosed and claimed in the copending United States Patent Application Ser. No. 731,930, filed Oct. 13, 1976, entitled METHOD AND APPARATUS FOR MAKING MOLDS, which application is assigned to the same assignee as the present invention, which issued Oct. 24, 1978 as U.S. Pat. No. 4,121,646. More particularly, the mixing apparatus of the present invention is an improvement over the mixing apparatus disclosed in the aforesaid copending application and provides for precision control of the mixing and dispensing process in making sand molds.
2. Description of the Prior Art
A wide variety of mixing machines have been developed to provide resin bound foundry sand for mold making in foundries and the like. U.S. Pat. Nos. 3,773,299; 3,850,413 and 3,881,703 disclose foundry said mixing machines wherein two components of a resinous binder system are centrifuged outwardly against a curtain of flowing sand. U.S. Pat. Nos. 3,934,858; 3,943,991; 3,946,796; 3,994,332; 3,995,837; 3,998,260; 3,999,592; 4,000,770 and 4,039,169 disclose mixing systems wherein molding sand and binder is premixed and separately molding sand and a catalyst is also premixed. These two premixed mixtures are then mixed together just prior to delivery into the mold flask. Various other types of foundry sand and material blending machines are disclosed in U.S. Pat. Nos. 3,158,358; 3,917,235; 3,929,320; 3,964,732; 3,983,923 and 4,004,782. Some of these mixing devices employ rotating elements mounted for rotation about a vertical axes while others employ horizontal rotors.
It is an object of the present invention to provide a new and improved mixing apparatus for dispensing a mixture of molding said and binder onto a mold forming pattern.
It is another object of the invention to provide a new and improved mixing apparatus for the character described which is especially well adapted for use in a program controlled automatic mold making system.
More particularly, it is an object of the present invention to provide a new and improved mixing apparatus of the character described which is simple in construction and operation and which provides for easy servicing and maintenance.
Another object of the present invention is to provide a new and improved mixing apparatus of the character described which includes a mixing chamber divided into upper and lower sections wherein the flow of sand is intermixed with one component of a binder system in an upper chamber and a second component of the binder system is introduced into the lower section followed by a thorough mixing of all materials together before discharge from the mixing chamber into a mold flask.
Another object of the present invention is to provide a new and improved mixing apparatus of the character described including novel injector means for insuring better mixing of the components of the binder system and the sand in the mixing chamber.
Still another object of the invention is to provide a novel mixing apparatus having a mixing chamber which can be easily opened for clean out and which provides for ready removal of the rotor assembly when required.